Butter oil process



'Jan. 20, 1953 1. J. LUNDAL ETAL BUTTER OIL PROCESS Filed June 12, 1946 mmvroxs: 122 966 TIL-undead Md 42y Pfiaba'c/zazmr Patented Jan. 20, 1953 BUTTER OIL PROCESS Ingie J. Lundal and Roy P. Robichaux, Chicago, Ill., assignors, by direct and mesne assignments, to Cherry-Burrell Corporation, Chicago, 111., a

corporation of Delaware Application June 12, 1946, Serial No. 676,195

This invention pertains to improvements in the processing of dairy products. More particularly, this invention relates to improvements in a continuous process for the manufacture of dry, purified butter oil from butter.

Prior to the instant invention, the art of making butter oil from butter commonly involved the inefficient and costly steps of decanting the melted butter oil while in a liquid state from the remaining ingredients of the melted butter, as well as a series of protracted and expensive separation and re-separation operations in an effort to secure a reason-ably efiicient recovery of butterfat from the melted butter.

The heretofore commonly used method of making butter oil from butter also involved the use of protracted high temperature heating operations which normally were performed in the presence of oxidizable gases or dissolved oxygen, with the resulting objectionable oxidation of the product.

This application is a continuation in part of our co-pending application Serial No. 457,612, filed September 7, 1942, and entitled Method of Making Butter and Butter Oil Concentrate now Patent No. 2,407,612.

The structural aspects of the invention are claimed in the coopending application Serial No. 676,196, filed June 12, 1946, and entitled System for Making Butter Oil.

The present invention, therefore, has for its prime objectives the provision of a simplified, continuous and improved method of making pure, dry butter oil from the same or different lots of butter; in which a minimum quantity of equipment is required to perform the process; in which the pure dry butter oil is delivered in a pasteurized and deaerated condition either in granulated or finely crystallized form as desired; in which the pure dry butter oil is highly refined or purified and contains a minimum of moisture and non-fatty milk solids; in which the pure dry butter oil is stable with respect to oxidation changes under normal packaging conditions; in which the pack-aging of the improved butter oil product may be performed in the absence of preservative gases; in which the acidity of the fat content of the purified dry butter oil may be adjusted without retaining any of the flavors of the neutralization ingredients; in which the necessary manpower commonly required in the commercial production of pure butter oil is reduced to a minimum; in which the commonly used decanting and re-separating operations and high temperature atmospheric heating operations, as Well as the heating of the melted butter in the presence of oxidizable 13 Claims. (Cl. 99-119) gases or dissolved oxygen, have been eliminated, together with the normal resulting oxidative changes in the butter oil; and in which an efficient recovery of fats may be obtained with the use of a single separation operation.

The scope of this invention, as well as other objects and advantages will become more obvious to those skilled in the art of processing dairy products upon a careful consideration of the following descriptionwhen read with reference to the accompanying drawings, in which drawings there is set forth a diagrammatic representation of apparatus well adapted for use in the practice of the preferred variant of the present invention and the sequential operative arrangement of such apparatus. The diagrammatic illustration is in the form of a flow chart, depicting the flow of a butter or like dairy product while it is being. continuously purified and refined in the practice of the improved process of makingv pure dry butter oil.

The preferred manner of practicing the invention,'having reference to thedrawings, in which like numerals are used to identify like elements, involves the first step of supplying suitable quantities of butter, preferably atmospherically tempered and either in salted or unsalted condition to the coil type of vats l. A sufficient quantity of warm water within the temperature range of F. to F. is added to the butter in vats I from the taps 2 to produce a butter and water mixture within the vats lat a temperature above the melting point of butter and having a butteriat concentration within the range of 25 percent to 50 percent butterfat, preferably 30 percent to 40 percent butterfat.

The coil vats l', which are equipped with power operated, hollow, agitator coils, through which heat exchange medium, such as hot water, may be circulated, may if desired be of the type illustrated in the Patent No. 1,786,819.

The melted butter and warm water mixture is concurrently agitated and heated, if necessary, within the vats l to secure and maintain a dispersion of the ingredients of the mixture and to maintain the dispersed mixture at a temperature above the melting point, of butter. Such agitation and heating is obtained by the use in a conventional manner of the power driven heat exchange and agitation coil 3 within the vats l. While the standardized and heated butter and water mixture is thus being agitated and the ingredientsuniformly dispersed under conditions of thermal control within the vats I, a greatly diluted, neutralizing solution is added to the mixture before any appreciable quantity of heat in excess of that required to melt the butter has been added thereto. The neutralizing solution preferably consists of a caustic soda solution, which may be stored in a convenient receptacle, such as the storage chamber 4, from which it may be drawn into the vats I through a convenient pipe and valve arrangement, such as the pipe provided with valves 6. The acidity of the melted butter and water mixture is adjusted as desired, preferably until the acidity is less than cubic centimeters of normal alkali to neutralize the free fatty acids in 100 grams of :butterfat, or substantially neutral, and in someinstances slightly on the alkaline side.

Commonly, it is desirable to neutralize the butterfat within the mixture in the-vats I in excess of the neutralization desired in the finished oil product, so that on titration the free fatty acids content of the mixture in the vats requires less than 10 cubic centimeters of normal alkali to neutralize the free=fatty acids in 100 grams of fat. This procedure of neutralization involves the overeneutralization of the serum content of the water and melted 'butterxmixture, so as thereby to secure the proper neutralization of the free fatty acids which were brought .into the mixture by the melted butter.

The neutralized or standardized melted butter and watermixture inthe vats .I is then heated by means of the use of the heat exchan e and agitation coils 3, having a suitable heat exchange medium passed through .coils .3 to a temperature within the range of approximately 110 F. to 150 F. as may for convenience be indicated by thermometers I provided in the rats I. The mentioned heating operation must maintain the mixture at a temperature above the melting point of butter and is performed while the ingredients of the mixture are maintained in a condition of uniform dispersion. The preferred temperatures to which the mixture is heated depends upon the subsequent steps in the process as will .be .hereinafter pointed out.

As clearly indicated in the drawings, a plurality of vats I are used, preferablythree in number, so that upon the commencement of .the remaining steps in the Process it is possible, as soon as one tank is emptied through conduit I3 controlled by valve 9 to commence the emptyin of a second tank while the first tank is being refilled. When the second tank has been emp tied, the emptying of a third tank may be commenced while the second tank is being refilled, during which same time the liquid butter and water mixture, which has by this time been formed in the first refilled tank, may be neutralized or standardized, whereupon the entire procedure of emptying and refilling tanks I, 2 and 3 and the neutralization steps may then again be repeated, therebyenabling the maintenance of a continuous supply .of neutralized melted butter and water mixture from the series of .vats I for use in the remaining steps of the process.

From the conduit 8, the heated and'neutralized butter and water mixture is forced by pump I.0 through pipe II to and through a pressure type filter I2. From the pressure type filter I2, the

filtered mixture is forced through pipe I3 to and through a non-atmospheric pressure type heater I4 and thence through pipe I5 into a centrifugal, desludging type of separator I6. The pipes 8, I3 and I5 ,are preferably provided with indicating thermometers I1, I8 and I9, respectively, to in- 4 dicate the temperatures, respectively, of the neutralized and heated butter and water mixture upon being discharged from the vats I and the temperatures of the mixture before and after passing through the heater I4.

The pressure type filter I2 may, if desired, be of the general design illustrated in the Patent No. 1,750,997. It should be noted that the use of the filter I2 is optional, depending on the purity .of the butter being processed. The heater I4,

if desired, may be of the non-atmospheric pressure type of heater generally illustrated in the Patents Nos. 1,821,934, 1,988,548 and 2,281,754.

Under certain conditions in the operation of the present process it is not necessary to use a pre-heater I4 immediately preceding the separator I6. Obviously, when a preheater I4 is used, it is only necessary to heat the mixture in the vats I to a temperature slightly above the melting point of butter, preferably F., so as to enable the ;maintenance of a uniform dispersion of all of the in redients .in the neutralized mixture. The necessary additional heat to then raise'the mixture to the desired separating temperature of approximately 125 F. is then added bythe use ofa .preheater I4. In thoseinstances Where it is desired not to use a preheater I v4, then the butter and water mixture must be heated in .thevats I to such a temperature within the range .of F. to 150 F. to assure the retention of suificient heat in the mixture whilefiowing from the .vats I to the separator I6 thatthe temperature of the mixture, upon entering the separator I6, will preferably be approximately .F. Separating temperatures in excess of F. are not desirable.

The temperature of the mixture prior to separation should preferably be Within the range of 120 F. to 150 .F. to thereby, among other things, prevent possible .oxidative changes in the fat. Such oxidative changes commonly occur when the unprotected fats .are retained in the presenceof orexposed to atmospheric gases or other oxidizing gases while at the elevated temperatures of 150 F. or above. High temperatures of separation also 'tend to provide a hard, rubbery curdformedinspart of residual milk solid in the neutralized melted butter and Water mixture. The rubbery curd, if present, .willrfrequently tend to clog a centrifugal, desludging type of separator, and thereby reduce separation efiiciency. As before mentioned, the preferred separation temperature isapproximately 125 F.

The separator I6 into which is received :the heated and standardized mixture, consisting of melted butter and water orother suitable fluids, such .as milk and the likeand standardizing solutions which have been added to the melted butter, is preferably of the type commonly referred to asanoil desludging type of separator. Inthe separator It the butterfat or oil phase .of' the mixture is separated from the water or milk phase, as well as from the sludge or coagulated milksolid-and other impurities phase. The oil is discharged from the separator I6 through discharge spigot 28 and the water phase and sludge phase are discharged through spigots 2I and 32.2. respectively.

The s p rator I6 .is preferably adjusted so that the oil or fat separation product has a fat concentration of approximately 98 percent butterfat or in excess of 97 percent butterfat. During the preferred type of operation of the separator, the temperature of the oil being separated has beenso thermally adjusted prior to separation that the temperature of the oil discharged from the separator is approximately 125 F.

Upon discharge of the concentrated milk fat from the spigot 20 of the centrifugal separator l6, it is supplied through a suitable conduit 23' to the pump 24 and thence forced through conduit 25 to and through a preheater 25, preferably of the non-atmospheric pressure type. Suitable, non-atmospheric pressure type of heaters are illustrated in the Patents Nos. 1,821,934, 1,988,548 and 2,281,754.

From the heater 23 the heated mixture passes through conduit 21 to a vacuum type of pasteurizer 28. The vacuum type of pasteurizer 28 is preferably of the general design illustrated in the Patents Nos. 2,314,455 and 2,325,534. It may, however, if desired, be of any one of various, wellrecognized, vacuum types of pasteurizer designs available to the dairy industry. The conduits 25 and 21 are preferably provided with thermometers 29 and 38, respectively, to indicate the temperature of the separated oil before and after it passes through the preheater 26.

The vacuum type of pasteurizer 28, diagrammatically illustrated in the drawings, is preferably equipped with three processing chambers. In these three chambers the product is first heated and pasteurized by direct contact with steam, then subjected to steam distillation and deaeration and then to vacuum cooling in the order mentioned while the material passes through the vacuum pasteurizer while being subjected to progressively increasing degrees of vacuum or reduced pressure and temperature change while flowing through the three series-connected chambers. Suitable valve mechanisms are provided intermediate the chambers to provide for the regulation of the degree of vacuum or reduced pressure existing within the chambers and to provide for the thermal control of the heating and cooling operation Within the pasteurizer 28 and regulate the flow of the material from one chamber to another. If desired, the steam distillation chamber and the vacuum cooler chamber may also be provided With water jackets to aid in the control of the temperature of the product being processed. A particular advantage of the vacuum type of pasteurizer. illustrated in the drawings which is of the general type disclosed in Patents Nos. 2,314,455 and 2,325,534, is that the oil being processed is subjected to almost instantaneous heating by direct contact of the oil while in finely divided state with steam, possessing suitable heating qualities, whereby the proper pasteurization, heating and steam distillation of the product may be effected and excess moisture in the oil evaporated without producing any scorched or overheated or scorching effects in the processed oil.

The heated and concentrated butter oil passes from the conduit 21 at a temperature within the range of 150 F. to 180 F. preferably 175 F., into the upper portion of the first chamber 3| of the vacuum type pasteurizer 28. In the chamber 31 the oil is subjected to a reduced pressure measurable within the range of 4 inches to 8 inches of mercury, preferably 6 inches of mercury, and is gently intermingled and diffused while in droplet form with steam supplied into the upper portion of the chamber 3| by conduit 32 to thereby heat the oil to a pasteurizing temperature within the range of 19 F. to 205 F., preferably 200 F. From the chamber 3| the intermingled steam and heated oil is drawn through conduit 33 provided with an automatic control valve 34 into the second chamber of the vacuum type pasteurizer 28 by the effect of the relatively reduced pressure condition existing in chamber 35 with respect to the pressure condition existing in chamber 3|. The reduced pressure condition existing in chamber 35 when measured may be indicated to be within the range of 14 inches of mercury to 25 inches of mercury. The steam and oil mixture enters the upper portion of the chamber 35 in a tangential manner and flows in a swirling film down the inner walls of the chamber 35 toward the lower portion of this chamber. Chamber 35 is provided at its upper portion with a centrally disposed gas exhaust passage 36 connected to a suitable source of vacuum (not shown) whereby the desired degree of reduced pressure may be maintained in chamber 35 and through passage 33 and automatic valve 34 in chamber 3|. As previously indicated, the relative pressures in chambers 3| and 35 are controlled by the automatic valve 34. It is, of course, obvious and does not require any further explanation that the pressures existing in the various chambers of the vacuum type pasteurizer automatically determine the temperatures of pasteurization, steam distillation, and vacuum-cooling steps, which occur while the product being processed passes through the vacuum type pasteurizer 28.

In the chamber 35 the heated mixture is subjected to steam distillation and deaeration and is drawn from the lower portion thereof through conduit 31. The exhaust gases, as above indicated, are withdrawn from chamber 35 through the exhaust conduit 36. The flow of the steamdistilled product through the conduit 31 is controlled by the automatic valve 38, and passes from the conduit 3! into the upper portion of the third chamber 39, by the effect of the relatively reduced pressure condition existing in chamber 39 with respect to the reduced pressure condition existing Within chamber 35. The reduced pressure condition existing in chamber 39 when measured may be indicated within the range of 28 inches of mercury to 28 /2 inches of mercury. The steam distilled and deaerated butterfat enters the upper portion of chamber 39 tangentially and flows downwardly over the inner wall thereof in a swirling film. Likeunto chamber 35, the chamber 39 is provided centrally at the upper portion thereof with a gas exhaust conduit 48, connected to a suitable source of vacuum (not shown) for providing and maintaining the desired degree of reduced pressure within the chamber 39. Each of the chambers 35 and 39- may also, if desired, be equipped with jackets 4| and 42, respectively, as illustrated in the drawing, for use in the circulation of heat exchange medium, thereby to aid in controlling the temperature of the product being processed.

It is important to note that under the preferred conditions of operation, the steam supplied to the chamber 3| of the vacuum type pasteurizer 28 is highly purified and preferably contains a slight degree of super-heat, so as to avoid undue adulteration of the milk fat with conbutter on ts cause the evaporation .of all of'the moisture added to the butter oil .by the steam, as we'll-as evaporation of residual moisture and other volatile gases remaining in the concentrated butter oil supplied to the vacuum type of pasteurizer 28.from the heater 26. In the preferred type of vacuum pasteurization of the butter oil, the butter oil remains in the pasteurizer only long enough to assure pasteurization, suitable deaeration, "and extraction of objectionable volatile ingredients. It is important :as a measure of safety to assure the purity of the ultimate product'in 'th'eipreparation of highly purified dry butter oil that the temperature of the butter oil when discharged from the vacuum type of pasteurizer is appreciably in excess of the temperature corresponding to the degree of vacuum or reduced pressure existing within the last chamber of the vacuum type of pasteurizer. By observing this precaution, the purity of the highly purified, pasteurized and deaerated butterfat is assured.

The dry and purified butter oil is discharged from the vacuum type of pasteurizer through conduit 53 provided with thermometers at at a temperature preferably within the range of 135 F. to 150 F. As mentioned previously, it should be specific-ally noted that the butter oil in passing through the vacuum type pasteurizer is subjected in the different portions of the machine to different degrees of vacuum, increasing in intensity as the butter oil passes in sequence from chamber to chamber of the pasteurizer 28. Immediately preceding the discharge of the butter oil from the pasteurizer 28, the oil is subjected to a vacuum of a degree corresponding to 28 to 28 /2 inches of mercury as previously mentioned, and is discharged from the last stage of the vacuum type pasteurizer at a temperature within the range of 135 F. to 150 'F. It is important to note that this temperature is appreciably in excess of the temperature which would correspond to the degree of vacuum within the last stage of the vacuum type pasteurizer, in the event that free moisture were still contained in the purified, pasteurized butter oil. The men'- tioned condition with respect to the fact that the temperature of the butter oil dischargedfrom the last stage of the vacuum type pasteurizer is in excess of the temperature of that which would correspond to the degree of vacuum existing in the pasteurizer in the event that moisture had still been present in the butter oil, clearly indicates that all of the moisture or at least substantially all of the moisture which can possibly be exposed to the effect of the reduced pressure has been withdrawn from the pasteurized and deaerated butter oil. It is also important to note that the pure pasteurized butter oil, upon being discharged from the described vacuum type of pasteurizer, is devoid of dissolved or entrained gases.

As is well understood in the oil purifying or refining industry, it is exceedingly difficult to remove from oil, particular-y when at temperatures below the boiling point of water, all of the last traces of water remaining in a substantially purified oil. This is particularly true when such last traces of water are in minute globules or droplets uniformly distributed through the oil and not readily exposable to the effect of reduced pressure which may exist in certain processing apparatus. It is thought that in the present invention the preheating of the butter oil prior to the introduction thereof into theme- 8, uum type iof pasteurizer and the use of steam, preferably :slightly superheated steam, in the direct heating 'of the butter'oil, certain heating effectsznot well understood by the inventors are accomplished which when combined with the atomizing and film-flow effects, which take .place in the preferred type of vacuum pasteurizer heretofore described, bring about the complete elimination of moisture from the butter oil being processed at relatively low temperatures.

Under certain conditions it may be desirable not to use the heater 2e intermediate the separator I6 and the vacuum type pasteurizer '28. In theevent that it is preferred not to use the heater 26 intermediate the separator 16 and the pasteurizer 28, then it will be necessary to adjust the reduced pressures within the chambers of the pasteurizer 28 and the quantity of steam supplied to the first chamber 3| of the pasteurizer 28 in such a manner that the desired pasteurizing temperature may be secured within the butter oil as it passes through chamber 3|, even though the temperature thereof, upon entering the upper portion of the chamber M, is approximately equal to the temperature of F., at which temperature it was discharged from the separator l6. In any event, the range of pasteurizing temperatures remains within the temperature range of 190 F. to 205 F., and is preferably 200 From the conduit 33, the pasteurized and deaerated oil, which has been withdrawn from the vacuum type pasteurizer 28 at a temperature within the range of F. to F., preferably 135 F., may, if desired, be pumped by pump 35 through conduit 16 and discharged through spigot :3! controlled by valve 48 into any desired form of storage container or receptacle or into any suitable packages in which it may crystallize or granlate.

The crystallization or granulation of the pasteurized butter oil, if packaged directly without further cooling operation, will be of a coarse, granular, crystalline structure, in which the high melting point butterfats which have bee-n at least partially crystallized will settle to the bottom of the package in the form of coarse crystals or granules. Frequently, the lower melting butterfats collect at the upper portion of the package in the form of liquid oil.

In the event that it is desired to produce a more suitable and uniformly crystallized pure, dry butterfat, which is more suitably adapted to retain the desirable qualities and characteristics of the highly refined butter oil, and which is readily adapted for direct packaging due to its form-retaining characteristics, then the pasteurized, dry butter oil is preferably pumped by pump d5 through the conduit 46 into and through the continuous type of chiller or freezer 59. In the freezer 49 a substantial portion of the fat constituents of the complex butter oil are uniformly intermingled or mixed and crystallized in the form of small crystals by the continuous, con-current chilling and agitation of the product on passing through the chiller or freezer 49. Preferably the freezer 49 is of the super-atmospheric-pressure type of freezer operated at a pressure within the range of .5 pounds to 25 pounds per square inch, preferably 10 pounds per square inch pressure and at a suitably reduced temperature and at such a capacity as to super-cool the fat while passing therethrough in a period of time from one to four minutes, preferably 3 minutes, to a temperature within the range of 60 F. to 75 F., preferably 60 F. At this temperature, the crystallization in the super-cooled fat or butter oil has been sufficiently completed prior to discharge from the cooler so that it may be readily handled and directly packaged due to its then acquired substantially form-retaining characteristics. The cooled, pure, dry butter oil may be packaged directly upon the discharge of the product from the freezer through the conduit which is controlled by the valve 5i, and in which there is provided a thermometer 52, to indicate the temperature of the completely processed butter oil.

In the preferred method of practicing the instant invention a continuous pressure type of freezer is used. Such a freezer may be of the general design indicated in the Patent No. 2,309,424, and in the applicants parent application Serial No. 457,612. In such a freezer the product is concurrently agitated and chilled While continuously passing through a freezer under super-atmospheric pressure within the range of approximately 5 to 25 pounds per square inch, preferably pounds per square inch, and in a period of time within the range of from one to four minutes, preferably three minutes. Such a freezer is also equipped with the necessary means for introducing metered quantities of gas into the product being chilled in the event that it is desired to incorporate gas in the product. By this expedient preservative or other gases may be uniformly dispersed and incorporated in the chilled butter oil.

Certain slight adjustments in the suggested temperatures for use in the different steps of 'the process may be required to make suitable adjustments for the milk fat characteristics present in different types of butter. It may also be desirable to make suitable adjustments for the type of processing to which the butter being converted into butter oil has previously been subjected. In considering the previous processing of the butter, one of the important aspects of such previous processing consists of the previous neutralizing processing of high acid creams from which the butter was originally made.

It is also important to note that when the butterfat or solidified butter oil is discharged from the chiller or freezer 49, it is preferably super-cooled so that it may readily be handled in a substantially form-retaining condition at a preferred temperature of 60 F. solidified butterfat, which has not been super-cooled but which has been completely crystallized and has been cooled to a temperature of 60 F., is not always readily handled. This is probably due to the condition of complete crystallization which has taken place under the last mentioned conditions. 7

Obviously, the important factor in securing :the desired low temperatures in the chilled butvariant of the present invention, it is desirable to adjust the pH of the serum portion of the butter dissolved in the vats I to the alkaline side of the neutral point, that is, to a pH of approximately 8. In those instances where the processing apparatus includes the heating units imediately preceding the vacuum type pasteurizer, then it 10 is desirable to heat the melted butter and-warm water mixture in the vets I to a temperatureof approximately F. The mixture, after being suitably standardized or neutralized in the vats I, is passed through the filter l2 and is then heated in preheater M in the absence of substantially any exposable or entrained gases to a temperature of approximately F. The heated mixture then passes to separator l6 and the separated butter oil or separation product is discharged therefrom at a temperature of approximately 125 F. The separated oil or separation product, discharged from the separator I6, is then heated in the absence of substantially any exposable or entrained gases in the heater 26 immediately preceding the admission of the oil into the vacuum type pasteurizer 28 to a temerature within the range of F. to F., preferably 175 F. The heated oil or separation product, upon being introduced into the first chamber of the vacuum type pasteurizer 28, is then further heated by direct contact with steam to a temperature within the range of F. to 205 F., preferably 200 F. The degree of exposure of the separation product to the reduced pressure conditions within the vacuum type pasteurizer 28 is so adjusted that the temperature of the butter oil or separation product, upon being discharged from the vacuum type, pasteurizer 28, is within the range of 135 F. to 145 F., preferably 140 F. From the pasteurizer 28 the pasteurized, purified, dry separation product or butter oil flows to a continuous type superatmospheric pressure freezer or cooler, in which the product is simultaneously agitated and cooled for a sufiicient period of time within the range of one minute to four minutes, preferably three minutes, to solidify a substantial portion thereof and to uniformly distribute the solidified butter oil as well as any minute quantities of remaining material other than butterfat in the cooled product. This freezing operation may be performed in the presence of a controlled quantity of gas, if desired, as heretofore mentioned, and the product is preferably so colled as to discharge the same from the freezer in a supercooled and form-retaining condition and at a temperature of approximately 60 F.

At the commencement of the operation of the process it is normally desirable to by-pass a reasonable quantity of pasteurized butter oil first discharged from the pasteurizer 28 and to return such by-passed product to one or more of the vats l until the system, including the filter, heaters, separator and pasteurizer, has been purged of moisture.

During the normal operation, the centrifugal separator 16 is so adjusted as to secure a butterfat concentration in the oil phase of the separation product preferably within the range of 98 /2 percent to 99-p1us percent. The freezer or chiller 49 is preferably operated at a pressure of approximately 10 pounds per square inch and the material passing through the freezer is exposed to a suitable cooling effect for a suitable period .of time so as to produce a super-cooled, purified butter oil having a temperature of approximately 60 F. and in substantially form-retaining condition when discharged from the freezer.

It will be observed from the preceding description of the improved process for the manufacture of pure, dry butter oil from butter that the present invention provides a simplified process for converting butter whether or not from different lots of butter, having varying characteristics.

into a uniform, highly purified, dry butter oil, possessing unusually satisfactory keeping and flavor qualities. Thepresent process, as hereinbefore pointed out, provides a method for the manufacture of pure, dry butter oil from butter, in which the final product'may be-packagedeither in liquid or partially solidified form, as desired, and in which the product may be so processed as-to possess certain specific types of physical characteristics, particularly with respect to the crystalline structure of the product. The improved process, hereinbefore described, due to the absence of' atmospheric'exposure of the product while at high temperatures during the processing thereof, provides a method for producing a highly refined, substantially stable, unoxidized, substantially pure, drybutter oil.

It will be appreciated by those skilled in the art that in a system for the manufacture of purified, dry butter oil or fat from butter in accordance with the teaching of the present invention, various-modifications, someofwhich have been suggested in thepreceding description, may be-mad'e without departing from the scope of the invention. Accordingly, it is desired that thisinvention shall not be limited to the specifically described arrangement, but that due latitude should'be-allowed in the interpretation of the invention.

Having thus described the-illustrated and preferred variant ofthis invention in an improved process for the manufactureof pure, dry butter oil, the invention is not to be restrictedto the specifically illustrated and preferred arrangement-of apparatusfor the practice-of the inven-- tion or to the specifically described steps of the process, as hereinbefore set forth, excepting insofar as necessary by't-heprior art disclosures and the appended claims.

The invention is herebyclaimed as follows:

1. The method of producing dry butter oil which comprises the steps ofmelting butter in Water having a temperature of approximately 110 agitating andconcurrentlyheating said mixture to secure and maintain a substantially uniform dispersionof the-ingredients of the mixture while at a tempera-tureabove themelting point of butter, adding an acid neutralizing agent tosaid mixture to reduce the acidity thereof to substantially the neutral point while continuing the agitation and concurrent heating of saidmixture, increasing the temperature of the neutralized mixture to a temperature within the range of 120- F. to 150 F.- while continuing the agitation of'the-mixture, filtering the neutralized mixture, attempering the filtered mixture toa separating temperature within the rangeof 120 F. to 150 F;, promptly separating the attempered mixture to secure a separation product having a butter oil content withinthe range of 94 percent to 100 percent butter oil at a temperature within the range of 120-E. to 150 R, attempering the separated butter'oil to a temperature Within'the range of 1'70 F; to 180'F;, pasteurizing the attempered butter oil at "a temperature within; the range -@195 F; to 205 F., andchillingthe pasteurized butter oil to atemperature within therange, of 60F; to 70F.

2. The method of producing dry butter oil which comprises the steps of melting butter in waterhaving atemperature within the range of 80 F: to 120- agitating and concurrently heatingsaid mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of butter, adding an acid neutralizing agent to the mixture until the acidity of the mixture is substantially neutral, increasing the temperature of the neutralized mixture to a temperature of approximately 125 F. While continuing the agitation of the mixture, filtering the-neutralized mixture, promptly separating the filtered mixture to secure a separation product having a butter oil content Within the range of 94 percent to 100 percent butter oil at a temperature of approximately 125 F;, attempering the separated butter oil to a temperature of approximately 175 F., pasteurizing the attempered butter oil at a temperature of approximately 200? F., and rapidly. chilling the pasteurized butteroil-"to. a temperature of approximately F.

3. The method of producing dry butter oil which comprises the steps of melting butter in Water having a temperature within the range of F; to. 120 F., agitating and concurrently. heating. said mixture to secure; and maintain a. sub.- stantially uniform dispersion of the ingredients of the mixturewhile at a temperature abovethe melting; point of. the butter content thereof, adding an acid:neutralizing agent'to said mixture until the. acidity of'jthe-mixture has. been so adjusted that upon titration the free. fatty acids content of the butterfat requires less than 10 cubic, centimeters of normal alkali to neutralize the free. fatty acids in gramstof butterfat, increasingthe temperature'of the. neutralized mixture to a temperature withinv the: range of F. to 150 F. While, continuing to agitate the. mixture, filtering the; neutralized. mixture, attempermg the. filtered. mixture. to; a. separation temperature: of approximately 125 FL, promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 9 8-percent butteroil at a temperature of approximately 125 F., attempering the separated butter oil. to a temperature of approximately l75 F., subjecting the attempered butter oil to the eifect of reduced pressure and increased temperatures for-a sufiicient periodof time to effect the deaeration and pasteurization of the separation product, and rapidly chilling the pasteurized and deaerated butter oil to a tempera-ture of approximately 60. F.

4, The method of producing dry butter oil which comprises the steps of melting butter, in water having a temperature Withintherange of 80 F. to -F., agitating and concurrently heating said mixture to secure,- and maintain a substantially uniform dispersion of the ingredients of the mixture while at atemperature above the meltingpoint of butter, adding an acid neutralizing agent to saidmixture until the acidity of the mixture has been so adjusted that upon. titration the free fatty acids content of the butterfat requires lessthan 10 cubic centimeters of T 6 normal alkali to neutralize the free fatty acids in 100 grams of butterfat, increasing the temperature of the neutralized mixture to a. temperature within the range of 110 F; to 150 F. while continuing tov agitate the mixture, filtering the neutralized mixture, attempering the' filtered; mixture to. a separation temperature of approximately F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at atemperature of approximately 125 F., heating the separated butter oil to a temperature of approximately 1'75 F., subjecting said heated separation product to the eifect of reduced pressures measurable in inches ofmercury within the range of 4 to: 28 inches ofmercury while concur- 13 rently subjecting the separation product to increased temperatures not in excess of approximately 200 F. to thereby effect the pasteurization and deodorization and deaeration of the attempered separation product and the extraction of volatile ingredients therefrom, and chilling the pasteurized butter oil to a temperature of approximately 60 F.

5. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature within the range of 80 F. to 120 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixture until the acidity of the mixture is slightly alkaline, increasing the temperature of the neutralized mixture to a temperature within the range of 110 F. to 150 F. while continuing to agitate the mixture, filtering the neutralized mixture, attempering the filtered mixture to a separation temperature of approximately 125 F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperature of approximately 125 F., heating the separation product while under pressure and in the absence of substantially any exposable gases to a temperature of approximately 175 F., subjecting said heated separation product while passing through a pasteurizer to the effect of reduced pressures measurable in inches of mercury within the range of 4 to 28 inches of mercury while water having a temperature within the range of 80 F. to 120 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixture until the acidity of the mixture has been so adjusted that upon titration the free fatty acids content of the butterfat requires less than cubic centimeters of 6 normal alkali to neutralize the free fatty acids in 100 grams of butterfat, increasing the temperature of the, neutral ized mixture to a temperature within the range of 110 F. to 150 F. while continuing to agitate the mixture, filtering the neutralized mixture, attempering the filtered mixture to a separation temperature of approximately 125 F., promptly -separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperature of approximately 125 F., attempering the separated butter oil to a temperature of approximately 175 F., subjecting said attempered but-ter oil to the effect of reduced pressures measurable in inches of mercury within the range of 4 to 28 inches of mercury while concurrently subjecting the attempered butter oil to increased temperatures not in excess of approximately 200 F. to thereby effect the pasteurization and deodorization and deaeration of the separation product and the extraction of volatile ingredients therefrom, discharging the pasteurized and vacuum treated butter oil from the pasteurizer at a temperature within the range of 135 F. to 150 F., and subjecting the pasteurized butter oil to simultaneous agitating and cooling sufiicient to solidify a substantial portion of the butter oil and to uniformly distribute the crystallized portion of the butter oil and the material other than butter oil throughout the cooled product whereby to control the intercrystalline structure of the solidifying butter oil.

'7. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature within the range of F. to 120 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixture until the acidity of the mixture has been so adjusted that upon titration the free fatty acids content of the butterfat requires less than '10 cubic centimeters of 1 6 normal alkali to neutralize the free fatty acids in grams of butterfat, increasing the temperature of the neutralized mixture to a temperature within the range of F. to 150 F. while continuing to agitate the mixture, filtering the neutralized mixture, attempering the filtered mixture to a separation temperature of approximately F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperatureof approximately 125 F., attempering the separation product to a temperature of approximately I75 F., subjecting said separation product to the effect of reduced pressures measurable in inches of mercury within the range of 4 to 28 /2 inches of mercury while concurrently subjecting the separation product to increased temperatures not in excess of approximately 200 F. to thereby effect the pasteurization and deodorization and deaeration of the separation product and the extraction of volatile ingredients therefrom, discharging the pasteurized and vacuum treated separation product from the pasteurizer at a temperature within the range of F. to F., and subjecting the pasteurized separation product to simultaneous agitation and rapid supercooling sufiicient to solidify a substantial portion of the butter oil content thereof and to uniformly distribute the crystallized portion of the solidified butter oil content thereof and the material other than butter oil throughout the cooled product.

8. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature within the range of 80 F. to 120 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the-ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixmixture to a temperature within the range of 120 F. to. 150 F, while continuing to agitate the mixture, filtering the neutralized mixture,

attemp'ering the filtered mixture to a separation temperature of approximately 125 F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperature of approximately 125 F., attempering the separation product to a temperature of approximately 175 F., subjecting said separation product to the effect of reduced pressures measurablein inches of mercury within the range of 4 to 28 inches of mercury while concurrently subjecting the separation product to increased temperatures not in excess of approximately 205 F. to thereby effect the pasteurization and deodorization and deaeration of the separation product and the extraction of volatile ingredients therefrom, discharging the pasteurized and vacuum treated separation product from the pasteurizer at a temperature Within the range of 1 5 F; to 150 F;, and subjecting the pasteurized separation product to simultaneous agitation and rapid super-cooling under super-atmospheric pressure conditions to solidify a substantial portion of the butter oil content thereof and to uniformly distribute the crystallized portion of the butter oil content thereof and material other than butter oil throughout the cooled product.

9. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature of approximately 110 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixture until the acidity of the mixture has been so adjusted that upon titration the free fatty acids content of the butterfatrequires less than cubic centimeters of normal alkali to neutralize the free fatty'acids in 100 grams of butterfat, increasing the temperature of the neutralized mixture to a temperature in excess of 110 F. while continuing to agitate the mixture, filtering the neutralized mixture, attempering the filtered mixture to a separation temperature of approximately 125 F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperature of approximately 125 F., attempering the separation product while under pressure and in the absence of undissolved or entrained gases to a temperature of approximately 175 F., subjecting said attempered separation product to the effect of reduced pressures measurable in inches of mercury Within the range of 4 to 28 inches of mercury while concurrently subjecting the attempered separation product to increased temperatures not in excess of approximately 205 F., to thereby effect the pasteurization and deodorization and deaeration of the separation product and the extraction of volatileingredients therefrom, discharging the pasteurized and vacuum treated separation product from the pasteurizer at a temperature of approximately 135 F., and subjecting the pasteurized product to simultaneous agitation and rapid super-cooling while under super-atmospheric pressure conditions in the presence of a controlled quantity of gas to solidify a substantial portion of the butter oil content thereof, and to uniformly distribute the crystallized butter oil '16 and material other than butter oil throughout the cooled product.

10. The methodv of producing dry butter oil which comprises the steps of melting butter in Water having a temperature within the range of F. to 120 R, agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture While at a temperature above the melting point of butter, adding an acid neutralizing agent to said mixture until the acidity of the mixture has been so adjusted that upon titration the free fatty acids content of the but terfat requires less than 10 cubic centimeters of normal alkali to neutralize the free fatty acids in grams of butterfat, attempering the neutralized mixture to a temperature of approximately F. while continuing to agitate the mixture, filtering the neutralized mixture, attempering the filtered mixture to a separation temperature of approximately F., promptly separating the attempered mixture to secure a separation product having a butter oil content of approximately 98 percent butter oil at a temperature of approximately 125 F., heating said separation product while under pressure and in the absence of substantially any exposable gases to a temperature of approximately 175 F., subjecting said separation product to the effect of reduced pressures measurable in inches of mercury within the range of 4 to 28 /2 inches of mercury while concurrently subjecting said separation product to increased temperatures not in excess of approximately 205 F. to thereby effect the pasteurization and deodorization and deaeration of the separation product and the extraction of volatile ingredients therefrom, discharging said pasteurized and vacuum treated separation product containing butter oil from the pasteurizer at a temperature within the range of to F., and subjecting the pasteurized separation product to simultaneous agitation and rapid super-cooling while under super-atmospheric pressure within the range of 5 pounds to 25 pounds per square inch of pressure and while in the presence of a controlled quantity of gas for a period of time within the range of one minute to four minutes to produce a super-cooled product having a temperature within the range of 60 F. to 70 F., whereby a substantial portion ofv the butter oil content thereof is solidified and in which the crystallized portion of the butter oil and material other than butter oil is uniformly dispersed throughout the cooled product.

11. The method of producing dry butter oil which comprises the steps of melting butter in Water having a temperature of approximately 110 F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adding an acid neutralizing agent to said mixture until the acidity of the mixture has been so adjusted that upon titration the free fatty acids content of the butterfat requires less than 10 cubic centimeters of {6 normal alkali to neutralize the free fatty acids in 100 grams of butterfat, increasing the temperature of the neutralized mixture to a temperature in excess of 110 F. while continuing to agitate the neutralized mixture, filtering the neutralized mixture, heating the filtered mixture to a separation temperature of approximately 125 F., promptly separating the heated and neutralized mixture to secure a separation product having a butter oil content of approximately 93 percent butter oil at a temperature of approximately 125 F., heating the separation product to a temperature of approximately 175 F., subjecting said separation product while passing through a vacuum type pasteurizer to the effect of reduced pressures measurable in inches of mercury within the range of 4 to 28% inches of mercury while concurrently subjecting said separation product to increased temperatures not in excess of approximately 205 F. to thereby efiect the pasteurization and deaeration of the separation product, discharging the pasteurized and vacuum treated separation product from said pasteurizer at a temperature of approximately 135 F. and then promptly subjecting the pasteurized separation product to simultaneous agitation and rapid super-cooling while under super-atmospheric pressure of approximately pounds per square inch and while in the presence of a controlled quantity of gas for a period of time of approximately three minutes to produce a super-cooled product having a temperature of approximately 65 F. in which a substantial portion of the butter oil content thereof is solidified and in which the solidified portion of the butter oil and material other than butter oil is uniformly dispersed throughout the cooled product.

12. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature within the range of 80 F. to 120 R, agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adjusting the pH of the serum portion of the butter contained in the mixture to the alkaline side of the neutral point, increasing the temperature of the adjusted mixture to a temperature within the range of 110 F. to 150 F. while continuing the agitation of the mixture, heating the mixture to a separation temperature of approximately 125 F., promptly separating the heated mixture to secure a separation product having a butter oil content of approximately 97 percent butter oil, heating the separation product to a temperature of approximately 175 F., and concurrently subjecting the heated separation product to the effect of reduced pressures and increased temperatures for a sufficient period of time to effect the pasteurization and deaeration of the separation product.

13. The method of producing dry butter oil which comprises the steps of melting butter in water having a temperature within the range of F. to F., agitating and concurrently heating said mixture to secure and maintain a substantially uniform dispersion of the ingredients of the mixture while at a temperature above the melting point of the butter content thereof, adjusting the pH of the serum portion of the butter contained in the mixture to a pH of approximately 8, increasing the temperature of the adjusted mixture to a temperature within the range of 110 F. to F. while continuing the agitation of the mixture, heating the mixture to a separation temperature of approximately 125 F., promptly separating the heated mixture to secure a separation product having a butter oil content of approximately 97 percent butter oil, heating the separation product to a temperature of approximately F., and concurrently subjecting the heated separation product to the effect of reduced pressures and increased temperatures for a sufficient period of time to effect the pasteurization and deaeration of the separation product.

INGIE- J. LUNDAL. ROY P. ROBICHAUX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,210,918 Eigelberner Jan. 2, 1917 1,837,205 Cloukey et a1 Dec. 22, 1931 1,941,415 Parker et a1 Dec. 26, 1933 2,406,819 Farrall Sept. 3, 1946 2,407,612 Lundal et a1 Sept. 10, 1946 2,414,837 Riggs Jan. 28, 1947 

1. THE METHOD OF PRODUCING DRY BUTTER OIL WHICH COMPRISES THE STEPS OF MELTING BUTTER IN WATER HAVING A TEMPERATURE OF APPROXIMATELY 110* F., AGITATING AND CONCURRENTLY HEATING SAID MIXTURE TO SECURE AND MAINTAIN A SUBSTANTIALLY UNIFORM DISPERSION OF THE INGREDIENTS OF THE MIXTURE WHILE AT A TEMPERATURE ABOVE THE MELTING POINT OF BUTTER, ADDING AN ACID NEUTRALIZING AGENT TO SAID MIXTURE TO REDUCE THE ACIDITY THEREOF TO SUBSTANTIALLY THE NEUTRAL POINT WHILE CONTINUING THE AGITATION AND CONCURRENT HEATING OF SAID MIXTURE, INCREASING THE TEMPERATURE OF THE NEUTRALIZED MIXTURE TO A TEMPERATURE WITHIN THE RANGE OF 120* F. TO 150* F. WHILE CONTINUING THE AGITATION OF THE MIXTURE, FILTERING THE NEUTRALIZED MIXTURE, ATTEMPERING THE FILTERED MIXTURE TO A SEPARATING TEMPERATURE WITHIN RANGE OF 120* F. TO 150* F., PROMPTLY SEPARATING THE ATTEMPERED MIXTURE TO SECURE A SEPARATION PRODUCT HAVING A BUTTER OIL CONTENT WITHIN THE RANGE OF 94 PERCENT TO 100 PERCENT BUTTER OIL AT A TEMPERATURE WITHIN THE RANGE OF 120* F. TO 150* F., ATTEMPERING THE SEPARATED BUTTER OIL TO A TEMPERATURE WITHIN THE RANGE OF 170* F. TO 180* F., PASTEURIZING THE ATTEMPERED BUTTER OIL AT A TEMPERATURE WITHIN THE RANGE OF 195* F. TO 205* F., AND CHILLING THE PASTEURIZED BUTTER OIL TO A TEMPERATURE WITHIN THE RANGE OF 60* F. TO 70* F. 